Personally, I find myself using the 3 hit combo more often then any skill, the next in the list for worth it to me is: Up + Attack, comboed with Uplift + attack, still the three hit combo seems to be the best tactic thus far. when facing an enemy that has ranged I go with Fireball + Fireball or Fireball + three hit combo (use this one on goblins mostly). to me it feels like the combos just aren't worth it most of the time, like when I use the Up + Attack comboed with Uplift + Attack, I still have to hit the slimes one more time to kill them, which more often then not gets me hit, however if I just use the standard 3 hit combo the slimes are dead and 100% of the time don't get hit, now I haven't maxed out my upgrade chart yet, nor have I defeated the boss for slimes or goblins, so I'll see how it acts later, but so far the combos just don't seem to be worth it.
Just wanted to add my two cents into it